Livernois Head/Cam Package power loss confusion

[akley88]

My truck is a 2016 f260 6.2 which had S&B intake, stainless works long tubes and magnaflow exhaust tuned on 93 prior to getting the heads and cam package installed. Last time on the same dyno truck made 354.53whp/388.67wtq. After that dyno i did have larger tires installed. went from 275/70/r18 to 285/75/18. I also did a gear swap from 3.73 to 4.88s.

So the thing that i am getting confused on is after the heads and cams installed and tuned the truck has lost about 40 whp and about 20 wtq. I know the gears and tires can effect wheel power readings but wasnt expecting this much of a loss with the new heads and cams. In addition there was no need to adjust the WOT fueling tables. The AFR was fine. there was some minor adjustments needed at cruise and idle.

The same fuel was used as last time and ethanol content was within 1-3% of last time on the dyno. there is only the same codes that the truck had prior to the install which was cat inefficiency code. It almost seems like my static compression dropped.

Looking for any thoughts or ideas?

 

[TwizzleStix]

Yeah, you're likely experiencing what happens when aftermarket camshafts are installed without being aware of the total package required. In most packages like yours the pistons need changed, thinner head gaskets used, or the head milled down to decrease CC size where all or one of these are done to increase the compression. Depending on the cam specs of overlap, if the base compression isn't increased there is indeed a loss of dynamic compression (and power) because of too much overlap when intake and exhaust are open...

Go with forced induction. It's actually easier to make safe power increases.

 

[akley88]

so im better off removing these heads and selling them?
I spoke with Livernois when i was thinking about buying them and told them the goal of the truck and what it had done. Guess these are a waste and a whipple would have been smarter.

 

[CoronaRaptor]

I think you should add a whipple onto what you have now. But, so some more research, I'm no expert, but i think those heads flow a lot better than the stocks.

 

[MTF]

I posted in your other thread

New Member, have a 6.2 but not a raptor | Ford Raptor Forums

 

[akley88]

I did reach out to livernois about the issue and they said they would get back to me.

 

[B E N]

Could be a few things, dyno variations, temp and DA, tuning issues, and of course tires/gears. Is this at the same dyno that was used last time? Dyno numbers can be 10% different just from a dynojet to a mustang. You should be running more RPM with the cam kit installed. If it is on the same dyno I would be looking at the tune. Thing is, the stock heads flow pretty good, the porting doesn't do that much on its own. And you need to wring the engine out to get the most out of the cams, plus cams are notoriously tough to tune for.

And yeah, a Whipple would have been way more gain for the money.

 

[akley88]

Same dyno has been used for all testing. The afr was showing no more fuel was needed at WOT. Some adjustments were needed at idle and cruise.

After talking to two other engine builders it just seems like static compression was lowered. We forgot to take photos of the combustion chambers to check if they were ported as well.

 

[MTF]

The Stage 1 heads are not, the Stage 3 heads are slightly ported and polished.
At least from the last time I talked to Livernois.
The Stage 3 kit is setup for forced air induction in mind.

Having said that the Livernois Stage 1 heads out flow stock.
Most of the extra flow and power gain comes from their custom valve seat grinding.

 

[akley88]

guess the guy i was talking to then didnt understand that the truck would be staying N/a for awhile and was a daily driver/tow vehicle.